Islamabad: A worshipper at the Shiite mosque in Islamabad where dozens were killed in a suicide blast on Friday described an “extremely powerful” explosion tearing through the building just after prayers began.

Muhammad Kazim, 52, told AFP he arrived at the Imam Bargah Qasr-e-Khadijatul Kubra mosque shortly after 1pm (0800 GMT) and took a place around seven or eight rows from the imam.

“During the first bow of the Namaz (prayer ritual), we heard gunfire,” he said outside the Pakistan Institute of Medical Sciences (PIMS) hospital, where many of the wounded were treated.

“And while we were still in the bowing position, an explosion occurred.”

Kazim, who is from Gilgit-Baltistan in northern Pakistan and lives in Islamabad, escaped unharmed but accompanied a wounded friend to the hospital.

“It was unclear whether it was a suicide bombing, but the explosion was extremely powerful and caused numerous casualties,” he said.

“Debris fell from the roof and windows were shattered. When I got outside, many bodies were scattered… many people lost their lives.”

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The Islamic State group has claimed responsibility for the attack, according to the SITE Intelligence Group, which monitors jihadist communications.

Another worshipper, Imran Mahmood, described a gunfight between the suicide bomber, a possible accomplice and volunteer security personnel at the mosque.

“The suicide attacker was trying to move forward, but one of our injured volunteers fired at him from behind, hitting him in the thigh,” Mahmood, in his fifties, told AFP.

“He fell but got up again. Another man accompanying him opened fire on our volunteers,” he added. “The attacker then jumped onto the gate and detonated the explosives.”

By Saturday morning, the death toll had risen to 31, with at least 169 people wounded.

The attack was the deadliest in the Pakistani capital since September 2008, when a suicide truck bomb destroyed part of the five-star Marriott hotel and killed 60 people.

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Calls for better security

Describing the aftermath, Kazim said uninjured worshippers rushed to help those wounded.

“People tried to help on their own, carrying two or three bodies in the trunks of their vehicles, while ambulances arrived about 20 to 25 minutes later,” he said.

“No one was allowed near the mosque afterwards.”

Kazim, who had been attending Friday prayers at the mosque for “the past three to four weeks”, said security had been lax.

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“I have never seen proper security in place,” he said. “Volunteers manage security on their own, but they lack the necessary equipment to do it effectively.”

“Shiite mosques are always under threat, and the government should take this seriously and provide adequate security,” he added.